Emergence
Physics does not determine every facet of biology! Biology is a great example of what is called emergence - the phenomena where the composite of many simple entities has properties that the entities themselves do not possess (and which are not always predictable on the basis of the prop...
If "Physics does not determine every facet of biology! " then you should give an explicit example of where the basic physical laws are in principle insufficient to explain some fact in biology. The examples you show are all cases where it is simply way to complex to do it ab initio from the physical laws. In your programming example you are e.g. ignoring the fact that you should also describe the programmer. 1/2
And let us not forget: "emergence" means that there are some collective phenomena that come as a surprise from considering the physical laws. It does not mean that the physical laws are unable to explain it or that we need something outside the physical laws. It just means that we haven't yet found the link between the fundamental and the effective theory. 2/2
@Oбжорoв - What you say is true, but I don't think it is what he meant. He is saying physics is like a dictionary. Biology is like poetry. You need a dictionary because you need to know what words you can use. But you also need something more to describe how words can be put together in pleasing and grammatically correct ways. Or in this case, can and have been put together.
@mmesser314 still I don’t agree. The something more is a person and that person can also be described in principle by fundamental physical laws. Maybe I am just a hardcore reductionist and don’t like it when people leave some opening for something out there that is in addition to the basic fundamental laws as we know them.
@vadim I am probably nitpicking, but if you mean to come up with practice and useful description of the areas like biology, physics is not sufficient in the sense that it is way too complex to try to derive all biological phenomena from basic fundamental laws and you will always need some phenomenology, then I agree. But in principle I believe (and yes it is a belief) that ultimately everything follows form the physical laws. There simply is nothing else. And to be 100% clear, that does not imply that chemistry, biology, etc are in any way "lesser" sciences, imo.
@Oбжорoв - Will you at least agree that something more is needed to constrain what biology is possible to the biology we actually find in nature? Something like initial conditions in a mechanics problem? And yes, those initial conditions are constrained by physics.
@Oбжорoв Physics as nature, underlies everything, but phsyics as science is not capable of describing everything. It is the nature of its method: it requires possibility of repeatable observations, manageable number of degrees of freedom, insensitivity to small changes of the parameters - all teh things that physicists udnerstand very well... but often forget, because these assumptions are usually satisfied in their research.
@mmesser314 I will agree that there are things we do not know yet, e.g. why things are as they are (e.g. your initial conditions). But that does not imply that there is something more than physics. That just implies that there are things we, with our limited human brains, don't know and maybe will never know.
@Oбжорoв No one is saying there is something more than physics. The point being made is that physics encompasses more than just biological systems. Physics itself will not tell you what part of physics counts as biology and what part of physics does not count as biology. You need something else to tell the physics what can / cannot be applied to biology. That doesn't mean physics cannot explain everything, it just means you have to help it along the way.
Here's lots of pretty illustrations regarding your summary of biophysics... google.com/… Nearly everything in biology has temperature, weight, electrical charge, momentum, gravity, motion... So the shape of a bird's wing is obviously best studied using physics!
Physics does not determine every facet of biology! Of course it does. Now, humans do not have the capacity yet to use mathematical models of physics to derive these emergent biological phenomena, but that doesn't at all imply that the same physics is not driving biology by the same rules we have come to understand in the physics laboratory. Just because we don't yet understand exactly how physics drives biology does not mean that physics doesn't drive biology.
@BioPhysicist No, I understand and agree with the point in this answer. It's just incompatible with the opening statement. Perhaps it's just semantics, but I guess as a physicist I take "Physics" to mean "nature" and not "the body of academic knowledge we have accumulated about nature". The latter is insufficient to describe biology; the former must, however. The alternative would be to suggest that there remain unidentified forces in the universe that conspire to produce biological phenomena against the understood forces of nature. I feel that is unlikely.
@J... As I noted in one of the comments above: "Physics as nature, underlies everything, but physics as science is not capable of describing everything." Perhaps, I should add a clarification to my answer - I see too many people interpreting it as an attack at the foundations of science, which it is not.
@Vadim I wouldn't say it feels like an attack - it seems more to express a certain philosophical view of physics that is contentious, however. There is no debate that the science of Physics cannot yet fully model biology, but the word "determine" is a rather strong one with heavy implications. +1 from me, in any case. I mean, even for emergent phenomena we can run the underlying equations to produce the emergent or chaotic behaviour - we can see that the simple laws we understand produce complex results, and to some degree we understand how. The surface area for true mystery is small.
Don't you think it is somewhat over the top to suggest in your answer that people who disagree with you on whether everything can be derived from physics have little clue about physics?
@NorbertSchuch Actually the comment in the brackets was intended for professional physicists, so that they do not take my criticism too close to heart - since these obviously understand the limits of applicability of the methods and the theories that they use. But I see now how it could be misinterpreted.
I would say that this statement is quite opinion-based (or leaves room for interpretation), and can well be understood as suggesting that people who believe that everything can be derived from the laws of physis have no clue about physics.
@NorbertSchuch I think it is quite obvious (to a physicist) that not everything can be derived from the laws of physics. Physics deals with certain classes of phenomena: those that allow repeatable observations, reducible to manageable number of degrees of freedom, robust to the initial conditions, etc. When we do physics we often take all these for granted, but when we compare physics to other fields of knowledge, we are aware of these limitations. Indeed, if everything is physics, then the division between physics, chemistry, biology, economics, linguistics, etc. would be meaningless.
@Vadim Yes, but the contention is that your statement, as worded, seems to suggest that perhaps it's not a question of our limited mathematical models, but that fundamentally the forces understood to govern reality are insufficient to explain more complex phenomena - and there I think is where people are getting stuck. That, even if you could solve all of the equations of physics for a system as complex as an animal cell (which we agree we currently cannot), that you still could not describe all of the processes in action - I don't think that's true or widely believed to be true.
@Vadim I think the current thinking in Physics is that while solving such problems is presently, and unarguably, intractable, I don't believe that there is any expectation that there are new, secret forces at work that we simply don't understand which Physics would agree are needed to bridge that gap. The gap is only one of computational complexity and not necessarily one where there is an identified gap in our understanding of the universe.
@J... Some problems are presently intractable and others are simply intractable. Take, e.g., statistical physics - we cannot describe motion of all the molecules - it is as fundamental a limitation as the speed of light or the uncertainty relation. So we come up with a whole new level if description, in terms of a small set of new categories. The more complex are the systems that we study, the more levels of description we need. At some point we simply do not call it physics anymore.
@Vadim On the contrary, I would say many professional physicists believe that stat. physics is an effective model which we could solve exactly if we had enough computational power. Just as cond. matter is something we could understand exactly if we had enough comp. power. To claim that there is a law of physics which forbids such an understanding and to put it on the same level as the impossibility of faster-than-light comm. or uncertainty relation is purely a belief (or a new axiom) and - if I were to follow you - unfortunately frequently used by people with little knowledge of physics.
@NorbertSchuch if we could have enough computational power is as problematic an assumption as if we could measure with infinite precision or instantaneously, which are at the core of QM and relativity. Once you think of how we measure or compute, the problems start to arise.
@Vadim I disagree strongly. There is accepted laws of nature which prevent us from measuring below the uncertainty relation or communicate instantaneously. There is no law of nature preventing us from building larger and larger computers, and there is no law of nature preventing us to come up with an ingenious idea of how to solve a gas of $10^{23}$ particles without the need of a large computer. No law of nature we know would break down if that would happen. So this is fundamentally different from laws of nature like the uncertainty relation, and claiming that someone who disagrees...
... with you on that point must be an amateur physicist who doesn't understand the matter is, to be honest, somewhat offensive.
No law of nature or physics prevents us from finding an algorithm which would simulate a large gas on a desktop computer. No law of nature prevents us from simulating gases on supercomputer - the reason why it is not done because we understand statistical physics and there is no need to do so, and we rather simulate weather forecasts. -- This is a fundamental difference to uncertainty relations - there's a law of nature forbidding something. Overcoming it would require to overthrow quantum physics. Being able to simulate large gases microscopically wouldn't overthrow anything.
@NorbertSchuch we need to be able to perform ab initio simulation of anything biological, to reduce it to just physics - from a single cell to human, to epidemies, to evolution. Otherwise it is not just physics
@Vadim That's a different question, and it depends on what you mean by the words "just physics". But you just put the difficulties in doing these ab initio simulations on the same footing as the uncertainty principle. I'd bet this is a minority opinion among professional physicists - and if it were true, it would be the most exciting thing, since it would mean that there is a fundamental physical principle we have not yet understood. (This feels a bit similar to Gil Kalai's claims that large-scale quantum computers are impossible.)
Discussion on answer by Vadim: Does p…
Discussion on answer by Vadim: Does p…